The Case of the Castle on Lockdown
by Pels
Summary: A post-Hogwarts What-If: non-epilogue compliant. Hermione is called back to Hogwarts to solve a mystery - but she's learned from her school days that logic trumps magic when it comes to investigating. First fanfic attempt, written for a class (with a word count limit)


**Disclaimer: I do not own Harry Potter (or Sherlock Holmes) - if I did I wouldn't be writing fanfiction for a college class in a teeny-tiny dorm room!**

 **Hermione Granger and the Case of the Castle on Lockdown**

Hermione stood, stunned, as the silver stag faded from her office, a familiar coin heating up in her pocket seconds later. It took a lot to startle her now. In the past five years as the Deputy Head of the Department of Magical Law Enforcement, she thought she was prepared for anything the Magical world could throw at her. Apparently she was wrong.

As she hurriedly grabbed her cloak, waving her wand to pack a small case, a thought forced its way into her mind, a conclusion she'd reached even before she first set foot into the Wizarding world. A reliance on magic had truly robbed the wizarding population of humankind's most valuable asset: logic.

"The Three Broomsticks!" she cried, throwing a handful of Floo powder before her as she leapt into the roaring fireplace, and disappeared into a swirl of green flames. Flashes of strange rooms appeared before her but she paid them no mind as she focused on her destination. Stepping briskly out of the fireplace into the bustling Inn, and paying little attention to the holiday greenery, she siphoned off the ashes as she weaved toward the door, waving a hurried acknowledgement to Madam Rosmerta.

She marveled at how normal this method of travelling now seemed and at how much she had learned since that fateful day when a strange professor, in an outfit more suited for Halloween than the Granger's quiet suburban neighborhood, had appeared on her doorstep. That day had passed in a blur, but she could still remember that vague feeling of dissatisfaction that colored her initial elation at the Professor's revelations.

Hermione nearly stumbled as she trudged out into the knee deep snow. Sighing, she transfigured her shoes into practical snowshoes for the journey. While she understood that the school was under lockdown – her pace quickened – she felt renewed frustration at the previous headmasters and headmistresses of Hogwarts for failing to consider a quicker route by which help could arrive. And, for the love of Merlin, why wasn't there an automatic alert to at least some outside source to alert help when the castle went on lockdown?

If she was honest with herself, this was just one more illogicality amongst the myriad she had experienced in the wizarding world. Even Dumbledore with all his years as an educator and a politician lacked all common sense, especially when it came to children. How had he not foreseen that telling schoolchildren a corridor was "out of bounds to everyone who does not wish to die a very painful death" would have the exact opposite effect? It had scarcely been a month before rumours began flying as the more daring students unlocked the door with a spell even a first year could learn. And giving a third year a time turner? She prided herself on being intelligent, but even she would admit that when weighing the benefits of more classes over the risk of time paradoxes and mental breakdowns, dropping Divination and Muggle Studies would have made much more sense. The Ministry-organized Tri-Wizard Tournament… well, that had been a mess from start to finish, but even on paper how had staring at a lake or a maze for an hour ever seemed to be a good idea?

She shook her head as the tightly closed entrance to the castle came into view. Scarcely a witch or wizard she'd met possessed even half the common sense of a muggle child, even in her own department. Then again, growing up with stories like "Babbity Rabbity and her Cackling Stump" instead of "The Adventures of Sherlock Holmes," perhaps it wasn't all their fault.

Pulling out her wand, Hermione prepared to cast a spell, but paused as a small figure appeared beside her.

"Professor Potty told Flossy to take you inside Miss Grangy!" The house elf, garbed in a miniature set of Hogwarts Robes, reached up for her hand and she cautiously grabbed it. With a POP the two appeared just inside the great oak entrance doors.

"Thank y–" A second POP and the small figure disappeared again. Hermione turned at the sound of hurried footsteps. "Harry!"

"Thank Merlin you're here Hermione," Harry sighed, brushing a hand through his hair, "I wasn't sure who else to call." He pulled her into a hug, before leading her further into the eerily quiet castle. They passed the Great Hall, bedecked with the usual giant Christmas trees and shimmering garlands, as Hermione furrowed her brow at her friend.

"Of course, I got your Patronus an hour ago." Starting up the staircase, she peered shrewdly at him. "I'd just heard 'Hogwarts on lockdown. Come at once if convenient' when I noticed this," she pulled the fake galleon out of her pocket, the words ' _If inconvenient, come all the same_ ' embossed across the top. "Honestly Harry, you nearly gave me a heart attack."

He looked sheepishly at her, rubbing his neck. "Well, what was I supposed to say? Minerva McGonagall's gone missing, the castle is somehow on lockdown, and I need your help to find out what happened?"

"Yes!"

"Oh."

"Just tell me what you've done so far. And where are the other teachers? The students are under lockdown in their dorms, of course." With that, Harry saw a change come over his long-time friend. Her gaze sharpened and her demeanor shifted into what she called her 'Holmes persona,' the reason she was appointed Deputy Head of the DMLE at such a young age.

"We only had eight students staying here over break so I volunteered to stay with the Headmistress and Mrs. Figg – our new caretaker, remember? – while the rest of the teachers left. The last time I saw her was at dinner last night." He furrowed his brow, "Nothing seemed different, but this morning I woke up to a castle on lockdown. I would've thought it would have woken me but –" Harry gave a huff of frustration as they waited for the staircase to turn their direction. "When my door wouldn't open this morning I just thought it was a prank. Can't you just imagine Fred and George pulling that?"

"But it wasn't a prank."

"No." The slight smile disappeared. "I ended up calling a house-elf to pop me into the hallway while I sent my Patronus to Minerva, but it didn't work. When I got to her room, well, you'll see for yourself, but she definitely wasn't there. I searched the Marauders' Map but she's not on it, and when I tried the fireplace Floo powder did nothing at all!"

"Harry. Calm down. Just take me to her rooms, alright?" He led her to a plain stretch of hallway, empty save for a portrait, although this too was empty.

Hermione held out a hand, stopping Harry in his tracks. She carefully examined the hallway around the portrait, paying close attention to the cracks in the stone floor around the entrance and across the hall from the portrait. She levitated two small metal buttons from a crack in the floor across the hallway from the portrait, looking at them closely. With a murmured "finite," one metal button was gone, replaced by a small beetle. "Beetles into buttons," she muttered, once more tapping the beetle.

"Accio buttons!" Hermione looked at Harry in alarm, but before she could stop him the incantation was complete. Nothing moved in the hallway, and she sighed.

"Well at least we know there aren't any more of them here, but _please_ , Harry, don't move things before I get the chance to see where they were. It may be nothing but it may be a clue." She stood up and faced the portrait. "And where is the portrait's guardian?"

Harry just shook his head. "There should be a young Scottish girl, but she wasn't here this morning. The portrait was open this morning too…" He trailed off as Hermione began examining the portrait.

Hermione lightly touched the canvas, inspecting a series of small dents in the paint, measuring their size against the buttons still in her hand. "Harry, take these will you?" She then pointed to her cloak, and with a whispered "Wingardium Leviosa," lifted herself until the top of the frame was at eye level. "Ah ha," she muttered under her breath, using her free hand to lift some threads from the top of the frame. She lowered herself carefully to the ground, and then peered closer at the threads. "Yellow." The witch conjured a small evidence bag with ease, placing the materials within.

She looked back to her friend and sighed. "Alright. Will we need to call another house elf or will the castle let you into her rooms?"

Harry tried to pull the portrait open but it didn't budge. "House elf again. None of the portraits have been opening for me this morning, even with the override password Minerva gave me in case of, well, emergencies. Flossy?"

With a familiar POP the house elf from earlier reappeared. "What can Flossy be doing for youse?"

Hermione smiled at the small figure. "Flossy, can you pop Professor Potter and me into Minerva's rooms?" With a nod, Flossy reached up, grabbed their hands, and popped them into McGonagall's rooms. As they appeared, Harry gasped. Hermione glanced around, cataloguing the rooms, before turning to look at Harry. The rooms matched Minerva McGonagall's office perfectly. They had appeared in an austere and functional sitting room, with two attached doors most likely leading to a bedroom and a bathroom. The room was spotless, not a book out of place or a cushion off kilter.

"Magic." Hermione closed her eyes, pinching the bridge of her nose. "I suppose this isn't what it looked like earlier, Harry."

"No – it was completely trashed earlier. Like the Gryffindor common room after a Quidditch win. That's why I knew something was wrong." He darted to the two opposite doors, pulling them open. Spotless. He spun, confused, in the middle of the room. "Is she back? Why is the castle still on lockdown?"

As Harry continued to ask questions, Hermione turned to Flossy. She knelt before the house elf. "Flossy, did you or one of the other house elves clean up Professor McGonagall's rooms after you brought Professor Potter in here this morning?"

"Yes Missy Grangy. We knows Professor Minnie hates mess, so Mrs. Figgy told Grundy to fix the mess for when Professor Minnie returns. Grundy's on break now, so Flossy is on duty."

Hermione closed her eyes in concentration but pressed on. "Do you know why she left Flossy? Can you find her?"

Flossy cocked her head to the side. "Professor Minnie never left. She could not leave while the castle is on lockdown." The small house elf scrunched her nose in concentration. "Flossy can't sense her in the castle though."

Harry approached the pair. "Flossy, how does the castle go on lockdown?"

The two friends held their breath as the little house elf began speaking.

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"Let me get this straight, Harry. The castle usually only goes on lockdown if the Headmistress or Headmaster tells it to, but the wards can be tied to their health. So if, for instance, a blonde ferret were to kill the Headmaster, say, on the Astronomy tower, the culprits wouldn't be able to leave the castle? And this wasn't implemented before such an occurrence, but only after an entire war was fought?" Hermione huffed in frustration at her best friend.

Harry just shrugged at his best friend. "Why did Dumbledore do half the things that he did? What I don't understand though is why we're going to talk to Mrs. Figg."

"Honestly Harry, don't you listen? 'Mrs. Figgy told Flossy' – that has to be Arabella."

They skidded around the last corner and headed for the portrait of Kneazles that adorned the door to Mrs. Figg's living quarters. Once more, Harry's silver stag leapt from his wand, passing through the frolicking kittens, alerting Mrs. Figg to their arrival, and, once more, Hermione sighed.

"So much for the element of surprise, Harry."

"Surprise?" Harry looked taken aback. "Why are we up here trying to surprise Mrs. Figg?"

Hermione couldn't help but smirk at his bewilderment. "Elementary, my dear Watson." She looked thoughtful. "Although, you know, Sherlock never actually said that." Her gaze focused again, as she looked at Harry. "Don't you find it suspicious? She's the caretaker, but why was she in Minerva's rooms earlier?" Hermione sped up as she rounded a corner. "And if she saw the mess and told a house elf to clean it, why didn't she go find you? And if she wasn't with Minerva when whatever happened, well, happened," she turned to look at Harry, "how did she know Minerva's rooms were a mess? There are too many questions, but maybe Mrs. Figg will be able to answer them."

Harry looked at her in amazement. "I'll never understand how you catch the smallest inconsistencies and come up with that many questions, but now that you say them it seems so obvious that something's wrong." He called for Flossy.

Hermione internally sighed. Here was where logic and morality collided for her. It made so much more sense just to use Flossy to travel across the castle – the time and effort they could have saved running from McGonagall's rooms to Mrs. Figg's – but using the poor house elf for transportation just felt wrong, and part of her rebelled against becoming so reliant on magic, even for transportation. She shook off her musings as the small elf popped them into the room before them.

As they reappeared, Hermione saw Mrs. Figg, her back to them, hurriedly closing the door to what appeared to be her bedroom. The yowling of a cat was suddenly cut off as the door shut firmly, and Arabella Figg turned to face her new visitors.

"Oh! Professor Potter, Miss Granger," The older woman greeted. She saw the house elf and her eyes widened for a second, hand instinctively twitching before checking herself. "Can I get you anything? Tea, biscuits?" Arabella crossed the room to the teakettle and the two friends suddenly noticed a young girl sitting curled up in a well-worn, flower printed armchair next to the fire. "I'd just put the kettle on to make Theodora and I some chamomile tea."

Harry nodded agreeably, but Hermione politely declined as she surveyed the room and its occupants. The young girl looked nervous, clutching a large stuffed lion toy. She couldn't have been much older than twelve. Her eyes were red and puffy, and there was something tense about her figure. Hermione crossed the room to crouch in front of the girl, kneeling on the rug which lay before the fireplace.

Smiling gently, Hermione introduced herself. "Hey Theodora. My name's Hermione. I'm a friend of Harry – Professor Potter." The small girl looked over to Arabella before releasing her grip on the stuffed lion and shaking Hermione's hand, still not speaking.

Mrs. Figg bustled over with the tea kettle. "Theodora came to my rooms after dinner last night. Feeling a mite homesick, aren't you dearie?" The girl nodded. "She's the only Hufflepuff staying over break and it gets lonely in those big empty dorms so I let her stay the night. I hope that's alright, Professor?"

Harry smiled at the girl. "Of course, that's perfectly alright. And it's Harry, Mrs. Figg, no need to be so formal. I'm not one for formalities among friends."

Rising and brushing soot off her robes, Hermione nodded in agreement before asking, "Mrs. Figg, Flossy told us you'd asked Grundy to clean up Professor McGonagall's rooms. Do you know what happened there?" She watched Mrs. Figg closely as the older woman placed three teacups on the table before the fire and poured hot water into each. Arabella turned to the cupboard, hand coming up once more, before walking over and gathering the containers of milk, sugar, and tea leaves.

"Well, this morning I tried to Floo Theodora back to her dorm but the fireplace wasn't working! So then I tried to walk the poor dear down, but my portrait is shut tightly and no spells –" Mrs. Figg cut herself off, then started again, "no spells Theodora tried, the dear, would open the door. She is only a second year of course, but isn't that odd that we couldn't get out?"

"Unfortunately the castle is on lockdown Mrs. Figg," Harry explained.

Hermione interrupted, "How did you know about Minerva's rooms?"

"Well, when we couldn't leave the room I called for my house elf and eventually it brought me to McGonagall's rooms," she paused, looking from Theodora to Harry, "I was looking for someone to explain what was going on, of course," looking back at Hermione "and when I saw the awful mess in there, well, I assumed it was some Gryffindor prank gone wrong like those Weasley twins used to do, so I told the house elf to clean it up before McGonagall got back." The older woman shook her head disapprovingly, "I'm sure she would be dreadfully angry to see that someone had trashed her room while she was gone so it seemed only polite."

Theodora spoke up for the first time, "Mrs. Figg let me stay here because we weren't sure what was happening with the rest of the castle. It's been so quiet all morning and I –" the small girl looked over at Mrs. Figg and went quiet. She clutched the toy closer to her chest, but the toy did not appear to comfort her, as her eyes went misty and she tensed, staring at it in silence.

Harry glanced at Hermione and opened his mouth to ask another question but the young Deputy Head beat him to it.

"Well, thank you very much Mrs. Figg, Theodora. We're figuring out why the castle won't let anyone leave their rooms, but in the meantime hold tight and we'll let you know when we've fixed the problem!" She smiled cheerfully at the pair, grabbed Harry's arm, and nodded to Flossy, who popped the two back into the hall outside the kitten portrait.

Her smile dropped abruptly. "Harry," she whispered urgently, "do you have the Map with you? Flossy, stay with us please."

Harry looked confused but began to pull the map out of his pocket.  
Hermione grabbed the map from him, hastily spreading it open and nearly hissing the command phrase. "There! Look right there," she pointed to the hallway they were in.

The young professor looked at the map, taken aback by her earnestness. He saw two names – Hermione Granger, Harry Potter. Then he noticed what the Deputy Head of the DMLE had noticed; in the room they had just vacated were three names, two nearly overlapping. Arabella Figg was pacing the wall of the small bedroom, but Theodora Nott's small name was partly covered by another – "Theodore Nott."

The two friends looked at each other, suddenly completely serious.

"Harry. Wand out. Stunners only." Without waiting for his confirmation, Hermione looked to the house elf waiting patiently beside them. "Flossy. This is very important. Can you pop Harry and me behind these two, right here?" Hermione pointed on the map, "Mrs. Figg isn't herself right now and Theodora might be in trouble."

The small house elf nodded her head frantically, and reached for the two humans.

As soon as Hermione's feet touched the ground in Mrs. Figg's sitting room, the young Deputy DMLE Head shot off two rapid-fire stunners, feeling more than hearing Harry do the same next to her. Startled at their abrupt re-entrance, the elderly woman standing beside the chair barely had time to spin around, holding out a long, thin piece of wood, before she was struck with three stunners and fell prone on the thick shag carpet next to the fireplace. The young girl slumped slightly in the chintz armchair as Hermione's second stunner hit the back of her head. Hermione only took a second to breathe a sigh of relief, thankful that this, at least, had gone smoothly, before she ran across the room to the bedroom. The young woman called out "Arabella Figg?" as she threw open the door, completely ignoring the sputtered questions of her confused best friend. Scarcely had the door begun to open when a streak of white burst through, mewling and panicked.

"Mrs. Figg, calm down. I need you to stand still. Harry, keep your wand out and I promise I will answer your questions in just a moment." Hermione pointed her wand at the suddenly still cat in front of her, carefully tracing patterns as she muttered a long incantation.

Harry watched in amazement as the small figure of the cat stretched and contorted, growing into the familiar shape of an older woman. The same woman who lay stunned before him. "Hermione, what–?"

Hermione found her arms full of an overwhelmed Mrs. Figg, but she did her best to answer Harry's partially asked question.

"The Mrs. Figg we just spoke with is an imposter – Theodore Nott, if the Map is correct, and since the map has never been wrong, I'd wager that in less than an hour we'll see an old schoolmate in place of your old babysitter. This Mrs. Figg is the real one."

"But," Harry looked between the two Mrs. Figg's before him, "How? Why?"

"Eloquent as always Harry," Hermione teased her friend. She led the true caretaker to a chair, helping her to sit. "That can wait for a second, though, I'm sure Minerva would like to be a part of this discussion too."

"Minerva? Wha–" Harry sat down on the arm of Mrs. Figg's chair, utterly bemused.

Hermione walked to the young girl, still slumped in her chair, and pulled the lion plush from her grasp. Setting the toy on the floor before her, Hermione once again began a long incantation, carefully sketching out shapes above the toy, brow furrowed in intense concentration. Like the cat Mrs. Figg only seconds before, the form of the lion toy slowly began to elongate and shift into the form of one Minerva McGonagall. Mrs. Figg and Harry watched in silence as the young woman before them uttered diagnostic spells over the newly un-Transfigured Headmistress. Hermione sighed in relief.

"Enervate."

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A few hours later found Hermione Granger, Harry Potter, Arabella Figg, and Minerva McGonagall sitting in an office in the Ministry of Magic, facing a wall that had been charmed to act like a one way mirror. On the other side they could see Sally-Anne Perks, Hermione's lead interviewer for the DMLE, sitting in front of a sullen Theodore Nott, enchanted quill writing away in a corner as it recorded the conversation.

"I still don't understand, Hermione. How did you know she – he – wasn't actually Mrs. Figg? How did you know where Minerva was? How did Nott even get into the school? How–" Harry paused mid question as Hermione laughed at him.

"It's all very simple, Harry. Mrs. Figg, Minerva, feel free to correct me if I get any part of this wrong, of course." Hermione settled back in her chair, watching Theodore Nott intently. "Theodore Nott is Theodora's older brother. Their parents were Death Eaters, captured after our fight in the Department of Mysteries, remember?" Harry nodded, so Hermione continued. "Theodore fought on Voldemort's side in the Final Battle and was captured. Professor McGonagall and I sat in at his trial after the war. I assume that he blamed her for not speaking up for him when she spoke for Daphne and Astoria Greengrass at the same trial – although, considering neither of them was actually a Death Eater and he was, I'm not sure what he expected her to do!" She huffed at yet another example of a lack of wizarding logic but continued speaking. "Anyways, Theodora came to Mrs. Figg's room last night on the pretense of being homesick. She asked to Floo her family and of course Mrs. Figg let her – a poor second-year girl, alone at Christmas time, what else could you do? And when Theodora opened the Floo connection, instead of just talking to her family, her brother came through the Floo and stunned Mrs. Figg."

"How could you possibly have known all of that?" Mrs. Figg stared at the young woman, astonished. "That's exactly what happened!"

Hermione smiled at the caretaker. "There was soot in the carpet by your fire – more soot than a magical fire would have produced just by heating a tea kettle – and there's usually a little bit of truth in every lie."

"But how did you know she – he – wasn't Mrs. Figg? We were only in there for a few minutes."

"Something was off about her from the beginning. She called you 'Professor Potter,' remember? She's known you since you were a baby and she only took the caretaker job this year, so you've only been 'Professor Potter' to her for about four months. It's unlikely that even if you were trying to be formal, Mrs. Figg, that you wouldn't slip up and call Harry, well, Harry, at least once during a casual conversation. The fake Mrs. Figg also had to look around for her tea things, and brought over three teacups without saucers, and no proper Englishwoman would forget to grab saucers. Every time she moved to grab another item she would twitch for a wand, but the true Mrs. Figg wouldn't have that instinct." Hermione took a breath and continued. "There were other clues, of course – talking about 'my house elf,' mentioning Weasley pranks as though she remembered them – but the biggest oddity was the yowling cat," she nodded to Mrs. Figg, "the fact that 'Mrs. Figg' just shut the poor dear in a room, and the lack of other Kneazles in the room. Kneazles are great judges of character, and I'm sure they all kicked up a fuss as soon as Theodore entered and attacked Mrs. Figg."

The three other occupants in the room looked at her in amazement. Harry shook his head, saying wryly "It always seems so simple once she explains it, but even when I was in the Auror Department I was never able to deduce nearly as much as she can."

Hermione laughed, and then continued. "Well, once he'd gotten Mrs. Figg taken care of, he took his sister up to Minerva's hallway and sent her down to cover the portrait with her scarf. Portraits often go wandering at night, and that is the only portrait in that hallway, so poor Theodora was able to cover it without anyone noticing. I assume professor's guardian portraits have the same spell on them that Professor Dumbledore used to inform him who was at his door, an alarm spell and a linked portrait that can identify the visitor. Her scarf, yellow and black for Hufflepuff, wouldn't have been quite wide enough, but it would have given them both a little more cover as they worked. Nott never could perform a decent disillusionment spell but he was quite good at transfiguration if I recall correctly."

Professor McGonagall nodded slowly. "My alarm spell went off during the night but Emilia didn't report a visitor so I ignored it at first, until I heard an odd clinking. I thought it must be a prank, so I opened the portrait…"

Hermione jumped in. "The clinking must have been this." She pulled the small metal buttons out of her pocket. "Beetles to buttons, second year. Metal though – that's a bit trickier, and the Nott family is known for their early grasp of Transfiguration." She looked over at Minerva. "You weren't expecting an adult to be outside your door, and so hadn't pulled out your wand. You did put up a good fight – Harry showed me his memories in the DMLE's pensieve, and while your rooms are now spotless they were quite a mess earlier. Once he managed to knock you out though, the wards immediately would have recognized your forced impairment and the castle went on lockdown. When he realized he couldn't use your Floo to take you out of the castle he would have used the only method he knew to keep someone from finding you before he could escape. He transfigured you into a stuffed lion and took his sister back down to Mrs. Figg's room, where he discovered he couldn't get back into the rooms there either. Self-transfiguration is difficult, but under stress and given time he managed to make himself look passably like Mrs. Figg. He called for his house elf, then a Hogwarts house elf, and set about setting up his own alibi, using his sister as proof. Telling Grundy to clean Professor McGonagall's rooms was easy, and he might have gotten away with it but he wasn't quite thorough enough. Harry had already seen that Minerva was missing and called for me. And the rest, I think, you all already know." Hermione sat back in her chair in satisfaction. "Now," she continued, "let us wait and see how close I was! Sally-Anne is truly wonderful at interrogation. Nott will be singing like a bird soon, and we can all, Theodora included – possibly with some counseling, Harry, make sure she gets that – go back to our normal lives!"

Harry laughed at the dumbfounded looks on both Minerva and Arabella's faces, so similar to his every time he heard Hermione explain her deductions. "Brilliant, Hermione!"

Hermione smirked, and teasingly turned her nose up at him, exclaiming with delight, "Elementary, my dear Harry!"


End file.
